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INDONESIA
Science and Technology Indonesia
Published by Universitas Sriwijaya
ISSN : 25804405     EISSN : 25804391     DOI : -
Core Subject : Science, Social, Engineering,
Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Environmental Science Materials Science & Nanotechnology Physics
An international Peer-review journal in the field of science and technology published by The Indonesian Science and Technology Society. Science and Technology Indonesia is a member of Crossref with DOI prefix number: 10.26554/sti. Science and Technology Indonesia publishes quarterly (January, April, July, October). Science and Technology Indonesia is an international scholarly journal on the field of science and technology aimed to publish a high-quality scientific paper including original research papers, reviews, short communication, and technical notes. This journal welcomes the submission of articles that covers a typical subject of natural science and technology such as: > Chemistry > Biology > Physics > Marine Science > Pharmacy > Chemical Engineering > Environmental Science and Engineering > Computational Engineering > Biotechnology Journal Commencement: October 2016
Arjuna Subject : -
Articles 24 Documents
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Search results for , issue "Vol. 9 No. 4 (2024): October" : 24 Documents clear
Analysis of Structure, Morphology, Magnetic Properties, and Microwave Absorption of Lanthanum Orthoferrite (LaFeO3) Naibaho, Marzuki; Widakdo, Januar; Kurniawan, Budhy; Nehan, Phahul Zhemas Zul; Vitayaya, Okvarahireka; Novita; Ramlan; Adi, Wisnu Ari; Ginting, Masno
Science and Technology Indonesia Vol. 9 No. 4 (2024): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.4.851-856

Abstract

LaFeO3 has been prepared using the solid-state reaction method with High Energy Milling (HEM). The preparation of LaFeO3 was carried out using stoichiometric calculations. Based on the XRD measurement results, single-phase LaFeO3 with an orthorhombic crystal structure was obtained. From the SEM results, the morphology of LaFeO3 is uniform, and the EDS results show the weight percentage of La, Fe, and O elements are 49.74, 21.08, and 29.18 wt%, respectively. VSM LaFeO3 results show magnetic saturation, remanence, and coercivity are 0.24 emu/g, 0.02 emu/g, and 853.38 Oe, respectively, and the absorption of LaFeO3 is -7.40 dB at a frequency of 6.02 GHz with a LaFeO3 sample thickness of 1.5mm.
Incorporating q-Rung Picture Fuzzy Frank Prioritized Weighted Aggregators with Multimoora Strategy for Decision Making Ramesh, Chitra; Kesavan, Prabakaran
Science and Technology Indonesia Vol. 9 No. 4 (2024): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.4.766-778

Abstract

The Frank norm operators and ˇq-rung picture fuzzy sets offer a versatile framework due to their adjustable parameters. Conversely, prioritized weighted operators are crucial for indicating the relative significance of alternatives and attributes. In this research, we have devised Frank’s prioritized weighted procedure for ˇq-rung picture fuzzy numbers. Thus, the ˇq-rung picture fuzzy prioritized weighted Frank averaging (ˇq-RPFPWFA) and geometric (ˇq-RPFPWFG) operators are presented and analyzed along with some of their properties. Utilizing these proposed operators, a novel approach is established, combining the enhanced MULTIMOORA (MM) procedure with unspecified weight data. A numerical example regarding the multiple attribute group decision making (MAGDM) problem of selecting the financial director of a residential society is handled based upon the aforementioned procedure. Furthermore, we have compared the results with those obtained using available operators. Evidently, the novel ˇq-RPFPWFA and ˇq-RPFPWFG aggregators with the MM technique yield reasonable and consistent outcomes for solving MAGDM.
Modelling of Claim and Pricing of Motor Insurance Based on Bonus-Malus System Considering the Frequency and Severity of Claims Hengcharoensuk, Jiramet; Phanmai, Konlawat; Moumeesri, Adisak
Science and Technology Indonesia Vol. 9 No. 4 (2024): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.4.904-913

Abstract

This article proposes new distributions for claim frequency and severity, specifically tailored for a bonus-malus system in automobile insurance. The mixed Poisson with weighted quasi Lindley distribution is recommended for modeling claim frequency, while the mixed exponential with weighted quasi Lindley distribution is suggested for modeling claim severity. To estimate insurance premiums, the Bayesian method is employed, incorporating both frequency and severity distributions. The study validates the proposed models using real data from an Australian insurance company, which includes 67,856 policies. The assessment of model adequacy indicates that the Poisson-weighted quasi Lindley distribution is a suitable fit for modeling claim frequency, while the exponential-weighted quasi Lindley distribution is appropriate for modeling claim severity. Overall, the results suggest that the proposed models offer optimal premium estimations, considering both claim frequency and severity, which can lead to fairer pricing and increased customer appeal during claim occurrences compared to conventional models.
Enhanced Anti-Inflammatory Activity of Kaempferia galanga Extract by Solid Self-Nanoemulsifying Drug Delivery System and Its Development in Fast Disintegrating Tablet Latifani, Salma; Fitriani, Annisa nur; Paniroy; Maesayani, Kadek Sanitha; Freddy, Juan; Adianingsih, Oktavia Rahayu
Science and Technology Indonesia Vol. 9 No. 4 (2024): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.4.840-850

Abstract

The increasing global incidence of osteoarthritis (OA) emphasizes the need for effective treatments, particularly for the elderly. Conventional OA treatments pose administration challenges, leading to patient discomfort due to difficulties in administration. Herbal formulations offer an alternative to mitigate these issues. Kaempferia galanga (KG) contains ethyl p-methoxycinnamate, a compound displaying anti-inflammatory properties that hold promise for OA treatment. This study explores the formulation of a solid self-nanoemulsifying drug delivery system (S-SNEDDS) of Kaempferia galanga extract (KGE) and evaluates its anti inflammatory efficacy, subsequently developing it into a fast disintegrating tablet (FDT) dosage form. Initially, a liquid SNEDDS (L-SNEDDS) was prepared with varying surfactant and co surfactant concentrations. The optimal formula of L-SNEDDS (FL2) using tween 80: cremophor RH 40: PEG 400 in a ratio of 1:1:2 demonstrated favorable characteristics, including transmittance of 86.93 ± 1.16%, emulsification time of 28 ± 2.65 s, particle size of 27.79 ± 2.00 nm, PDI of 0.21 ± 0.014, and zeta potential of -12.57 mV. FL2 was solidified using aerosil 200 to produce S-SNEDDS and tested for anti-inflammatory efficacy in vivo using a carrageenan induced rat model. Results showed enhanced anti-inflammatory efficacy of KGE via S-SNEDDS, marked by reduced edema volume. Afterward, FDT S-SNEDDS were prepared using the direct compression method by comparing different types of superdisintegrants. The formulation using the combination of crospovidone and croscarmellose sodium (FT2) demonstrated excellent flow properties, tablet disintegration time of 63 s, wetting time of 34.01 ± 7.87 s, friability of 0.19%, and hardness of 3.53 ± 6.16 kg/cm2. The dissolution test indicated a better dissolution profile for FT2 compared to other formulations. In conclusion, this research presents the potential of FDT S-SNEDDS as a promising drug delivery system for enhancing the therapeutic effects of Kaempferia galanga extract in treating inflammatory conditions such as osteoarthritis.
Relativity and the Magnitude of Velocities Ajeti, Musa; Berisha, Valbona; Klinaku, Shukri
Science and Technology Indonesia Vol. 9 No. 4 (2024): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.4.790-797

Abstract

In modern physics, relativity is primarily understood through the framework of Einstein’s theory. According to the special theory of relativity (STR), Galilean relativity serves as a very accurate approximation at low velocities, where ‘relativistic effects’ can be neglected. However, at high velocities, these effects become significant and are accurately described by STR. This paper challenges this understanding, arguing that the opposite is true. In Galilean relativity, the relativity of time is substantial and cannot be ignored. Thus, relative time is more negligible in STR than in Galilean relativity. By comparing Galilean relativity and STR through physical, mathematical, and specific examples, two conclusions are drawn: first, the current categorization of relativity theories based on velocity magnitude is artificial and inaccurate; second, the relativity of time can be ignored in special relativity, while it remains significant and cannot be overlooked in Galilean relativity.
Isolation and Characterization of Cellulose Nanofibrils (CNF) from Dates by-Product via Citric Acid Hydrolysis Aisy, Laaili Azti Rohaadatul; Kemala, Tetty; Suryanegara, Lisman; Purwaningsih, Henny
Science and Technology Indonesia Vol. 9 No. 4 (2024): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.4.818-827

Abstract

Industrial residues that are not optimally utilized are removed by burning, landfilling, or dumping, which can threaten the environment and health. In fact, part of this agro-industrial waste still has content that has the potential to become raw material for value-added other industries. Dates by-product as residue of the fiber-rich fruit industry have the potential to be a source of nanocellulose. This study aims to obtain nanofibril cellulose (CNF) isolates from dates by-product via citric acid hydrolysis, and investigate the effect of acid concentration on the unknown dates by-product CNF isolate characteristics. Pretreatment such as delignification and bleaching is needed to obtain cellulose isolate with high purity. Furthermore, acid hydrolysis, centrifugation, and sonication are performed to obtain CNF. CNF isolates are characterized by the analysis of particle size distribution, morphology, and crystallinity. Analysis of functional groups and lignocellulose content test confirm that lignin and hemicellulose are degraded during isolation. The particle size distribution measurement shows that the greater the acid concentration, the smaller the CNF size and the better the size uniformity. The morphology of the CNF obtained is net-like fibers. The degree of crystallinity shown decreases with increasing acid concentration. This study revealed that different citric acid concentrations can result in different characteristics of CNF isolates.
Methyl Ester Sulfonate (MES) Surfactant Production from Waste Cooking Oil (WCO) with Microwave Technology Qadariyah, Lailatul; Ryvalda, Dhea Septyanonie; Aditama, Narendra Yudha; Aswie, Viqhi; Mahfud, Mahfud
Science and Technology Indonesia Vol. 9 No. 4 (2024): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.4.929-940

Abstract

Traction Energy Asia 2020 reported that 3 million kilolitres of WCO were collected in Indonesia in 2019, 1.6 million kilolitres from urban households. WCO poses risks due to common reuse or disposal. Repurposing for MES surfactant is vital. Hence, this study aims to produce an MES surfactant from WCO feedstock using NaHSO3 as a microwave-assisted reactant by observing the influence of variables such as reactant mole ratio, catalyst concentration, sulfonation reaction time, and microwave power. The adsorption method involves vacuum filtration of WCO to remove impurities, mixing with activated carbon, and settling before a second filtration. Transesterification transforms WCO into methyl ester through mixing with methoxide solution with a molar ratio of methanol to WCO of 1:9 and a 1 wet% NaOH catalyst based on WCO, followed by washing and drying. Sulfonation involves reacting methyl ester with NaHSO3 (1:1, 1:2, 1:3, 1:4) and CaO catalyst (1%, 1.5%, 2%, 2.5%). The reaction occurs in a microwave at power variations of 300, 450, 600, and 750 Watts, as well as with variations in time of 20, 30, 40, 50, and 60 minutes. After that, it ends with purifying and neutralizing to produce MES. The optimal conditions for MES production are a 1:2 molar ratio of reactants, 1.5% CaO catalyst concentration, 20 minutes, and 450 W, yielding 48.06%. MES characteristics: pale yellow color, density of 0.859 g/cm3, viscosity of 1.780 cSt, and surface tension of 32.62 dyne/cm. FTIR analysis confirms sulfonic acid groups at 1195.27 cm−1 and 1169.1 cm−1 wavelengths.
Corn-Cob-Waste-Based Fe2.75Mn0.25O4/rGO Nanocomposite Application as Anti-Radar Coatings Saefullah, Lalu; Kormil Saputra; Wida Puteri Agista; Masruroh; Dionysius J. D. H. Santjojo; Istiroyah
Science and Technology Indonesia Vol. 9 No. 4 (2024): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.4.798-805

Abstract

Radar-absorbent materials (RAMs) have become essential technologies in fields that require them, such as the military. Their working principle is that they absorb electromagnetic waves and prevent their reflection. In developing the manufacturing of RAMs, high-performance materials are needed for effective use as RAMs. In general, RAMs possess two essential properties: magnetic and dielectric. This research reports the author’s successful synthesis of an Fe2.75Mn0.25O4/rGO nanocomposite as an anti-radar material using the coprecipitation method. Interestingly, the main precursors used were natural materials, namely iron sand and corn cob waste. XRD, FTIR, and SEM-EDX characterized the research samples to determine the nanocomposite’s structure and phase, functional groups, and morphology after doping. XRD characterization results showed that Fe2.75Mn0.25O4/rGO nanoparticles had a cubic crystal structure and that there were no new peaks, which indicates that Mn had been successfully substituted into Fe. FTIR test results showed that the Fe2.75Mn0.25O4/rGO nanocomposite had Mn and Fe-O functional groups in octahedral and tetrahedral positions at wave numbers of 418 480 cm-1 and that there were C=C functional groups at the wave number of 1629 cm-1. SEM results showed that the nanocomposite comprised Fe2.75Mn0.25O4/rGO particles in agglomerated spheres and corn-cob-based rGO in sheet form, with a grain size of around 26–31 nm. EDX test results showed the appearance of Fe, Mn, O, and C elements. It was also found that the 3-mm-thick Fe2.75Mn0.25O4/rGO nanocomposite sample achieved the highest reflection loss (RL) value of -43.6 dB at a frequency of 8.5 GHz, indicating a significant radar wave absorption capability.
Some Coefficient Problems for Subclasses of Holomorphic Functions in Complex Order Associating Sălăgeăn q-Differential Operator Yie, Tseu Suet; Janteng, Aini; Abbas, Muhammad
Science and Technology Indonesia Vol. 9 No. 4 (2024): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.4.981-988

Abstract

A function with complex values and at every point of the specific domain contains a derivative is commonly known as analytic functions which is also referred as holomorphic functions. We begin by interpreting \(A\) as the class for all holomorphic functions \(L(\xi)\) with a Taylor series expansion written in the form: \[L(\xi) = \xi + \sum_{i=2}^{\infty} x_i \xi^i\] where \(x_i \in \mathbb{C}\) and \(\xi \in D\). \(D\) is the open unit disk where \(D = \{\xi : \xi \in \mathbb{C}, |\xi| < 1 \}\). Furthermore, we suggest the subclass of \(A\) that is univalent in \(D\) represented as \(S\). It is commonly known that the main subclasses of class \(S\) are the class of starlike functions and the class of convex functions. To develop and analyze the Fekete-Szegö problems, the theory of geometric function contributes significantly to this. Moreover, the frequent use of \(q\)-calculus as a general direction of research among mathematicians has caught our attention. In this research, we attained the initial coefficients, \(x_2\) and \(x_3\), and the upper bound for the functional \(|x_3 - \nu x_2^2|\) of functions \(L\) in the two new subclasses that are introduced by involving the Sălăgeăn \(q\)-differential operator, \(M_q^\eta L(\xi)\) and the definition of subordination.
Characteristics and Dosimetric Properties of Tissue-Equivalent Thermoluminescent Glass Detector Based on Al-Li-Zn, Borate Oxide Dope Dy3+ Efenji, Godwin Irinam; Bin Mustapha, Iskandar Shahrim; Yusof, Nur Nabihah; Anthony, Rabba James; Kamgba, Ferdinand Ayim; P. O., Ushie; Hussein Khazaalah, Thair; Jamil , Munirah; Izwan, Muhammad Fadhirul; Aliyu, Umar Sa’ad; Ezra, Nabasu Seth; Oke, Aduragbemi Olaoluwa; Salah Naeem , Hayder; Muhammad , Alhassan; Idriss , Ali S. A.
Science and Technology Indonesia Vol. 9 No. 4 (2024): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.4.965-980

Abstract

Functionality and dosimetric properties of a tissue-equivalent thermoluminescent glass detector doped with Dy3+. This work investigated an Aluminium-Lithium-Zinc borate oxide matrix using the melting-quench method. X-ray diffraction confirms the glass sample is amorphous. Dysprosium ions doping raises the glass’s tissue equivalent effective atomic number (Zeff.), improving its ability to absorb radiation and its sensitivity, with reproducibility almost at the tolerable limit. The glass detector also reduces the fading rate and signal loss over time. The minimum detectable dose values were 53.04 mGy and 45.1 mGy for the un-doped and 1.5 mol Dy3+ doped Al-Li-Zn borate glasses, respectively. A bright peak was seen in photoluminescence spectra at 348 nm (yellow), 529 nm (green), and 625 nm (orange hue). These correspond to the Dy3+ transitions at 4H15/2 → 6P7/2, 4F9/2 → 6H15/2, 4F9/2 → 6H15/2, and 4F9/2 → 6H13/2 , respectively. There was a noticeable drop in Tg from 257°C in the undoped sample to 101°C in the doped sample, Tm from 862°C to 815°C, and Tc from 756°C to 444°C in the doped sample. These results may indicate a lower temperature at which the material transitions from a solid to a liquid state and a lower crystallisation threshold. The frequency component and energy of activation of the 1.5 mol Dy3+ doped Aluminium-Lithium-Zinc borate are 2.1×10 27 s-1 and 1.03 eV, respectively. The 1.5 Dy3+ doped Aluminium-Lithium-Zinc borate glasses exhibit promising dosimetric properties of the tissue-equivalent thermoluminescent glass detector, indicating its potential for accurate and consistent radiation dosimetry in various applications.

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